Rust 1.78.0 released

Version
1.78.0 of the Rust language has been released. Changes include a new
mechanism for diagnostic attributes, changes to how assertions around
unsafe blocks are handled, and more.

Rust now supports a #[diagnostic] attribute namespace to
influence compiler error messages. These are treated as hints which
the compiler is not required to use, and it is also not an error to
provide a diagnostic that the compiler doesn't recognize. This
flexibility allows source code to provide diagnostics even when
they're not supported by all compilers, whether those are different
versions or entirely different implementations.